| 摘要 |
<p>PURPOSE: To measure a deep natural resistance simultaneously with the measurement of azimuth natural resistance by injecting a measuring current into a stratum through the array of an azimuth current electrode arranged on a body movable within a bored hole. CONSTITUTION: The upper section 20 of the body 17 of a probe 12 movably suspended within a bored hole 11 contains an electric circuit. The cylindrical body 22 of a first intermediate section 21 supports a plurality of arrays 23 of azimuth electrodes mutually isolated in the circumferential direction, and a second intermediate section 24 supports an annular electrode. The body 26 of a bottom section 25 has a shoe 27 making contact with the wall of the bored hole 11 by a leaf spring 28. In order to measure the natural resistance in a plurality of directions around the bored hole 11, a current is injected from the azimuth current electrode Aazi into a stratum. This current is focused by an active feedback system comprising an azimuth monitor electrode Mazi, annular electrodes M3, M4 and two parts of a guard electrode A2.</p> |
